[PATCH 05/39] blk-mq: replace blk_mq_init_commands with a ->init_request method

Christoph Hellwig
2014-03-17T13:27:38Z

[-- Attachment #1: 0005-blk-mq-replace-blk_mq_init_commands-with-a-init_requ.patch --]
[-- Type: text/plain, Size: 6685 bytes --]

Bedides a simpler and cleared interface this also allows to initialize the
flush_rq properly. The interface for that is still a bit messy as we don't
have a hw_ctx available for the flush request, but that's something that
should be fixable with a little work once the demand arises.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
block/blk-mq.c | 65 +++++++++++++++++++++-----------------------
drivers/block/virtio_blk.c | 22 +++++++--------
include/linux/blk-mq.h | 9 +++++-
3 files changed, 50 insertions(+), 46 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index e3284f6..c2ce99b 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -996,33 +996,6 @@ static void blk_mq_hctx_notify(void *data, unsigned long action,
blk_mq_put_ctx(ctx);
}

-static void blk_mq_init_hw_commands(struct blk_mq_hw_ctx *hctx,
- void (*init)(void *, struct blk_mq_hw_ctx *,
- struct request *, unsigned int),
- void *data)
-{
- unsigned int i;
-
- for (i = 0; i < hctx->queue_depth; i++) {
- struct request *rq = hctx->rqs[i];
-
- init(data, hctx, rq, i);
- }
-}
-
-void blk_mq_init_commands(struct request_queue *q,
- void (*init)(void *, struct blk_mq_hw_ctx *,
- struct request *, unsigned int),
- void *data)
-{
- struct blk_mq_hw_ctx *hctx;
- unsigned int i;
-
- queue_for_each_hw_ctx(q, hctx, i)
- blk_mq_init_hw_commands(hctx, init, data);
-}
-EXPORT_SYMBOL(blk_mq_init_commands);
-
static void blk_mq_free_rq_map(struct blk_mq_hw_ctx *hctx)
{
struct page *page;
@@ -1050,10 +1023,12 @@ static size_t order_to_size(unsigned int order)
}

static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
- unsigned int reserved_tags, int node)
+ struct blk_mq_reg *reg, void *driver_data, int node)
{
+ unsigned int reserved_tags = reg->reserved_tags;
unsigned int i, j, entries_per_page, max_order = 4;
size_t rq_size, left;
+ int error;

INIT_LIST_HEAD(&hctx->page_list);

@@ -1102,14 +1077,23 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
for (j = 0; j < to_do; j++) {
hctx->rqs[i] = p;
blk_mq_rq_init(hctx, hctx->rqs[i]);
+ if (reg->ops->init_request) {
+ error = reg->ops->init_request(driver_data,
+ hctx, hctx->rqs[i], i);
+ if (error)
+ goto err_rq_map;
+ }
+
p += rq_size;
i++;
}
}

- if (i < (reserved_tags + BLK_MQ_TAG_MIN))
+ if (i < (reserved_tags + BLK_MQ_TAG_MIN)) {
+ error = -ENOMEM;
goto err_rq_map;
- else if (i != hctx->queue_depth) {
+ }
+ if (i != hctx->queue_depth) {
hctx->queue_depth = i;
pr_warn("%s: queue depth set to %u because of low memory\n",
__func__, i);
@@ -1117,12 +1101,14 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,

hctx->tags = blk_mq_init_tags(hctx->queue_depth, reserved_tags, node);
if (!hctx->tags) {
-err_rq_map:
- blk_mq_free_rq_map(hctx);
- return -ENOMEM;
+ error = -ENOMEM;
+ goto err_rq_map;
}

return 0;
+err_rq_map:
+ blk_mq_free_rq_map(hctx);
+ return error;
}

static int blk_mq_init_hw_queues(struct request_queue *q,
@@ -1155,7 +1141,7 @@ static int blk_mq_init_hw_queues(struct request_queue *q,
blk_mq_hctx_notify, hctx);
blk_mq_register_cpu_notifier(&hctx->cpu_notifier);

- if (blk_mq_init_rq_map(hctx, reg->reserved_tags, node))
+ if (blk_mq_init_rq_map(hctx, reg, driver_data, node))
break;

/*
@@ -1334,6 +1320,17 @@ struct request_queue *blk_mq_init_queue(struct blk_mq_reg *reg,
if (!q->flush_rq)
goto err_hw;

+ if (reg->ops->init_request) {
+ blk_rq_init(q, q->flush_rq);
+ if (reg->cmd_size)
+ q->flush_rq->special =
+ blk_mq_rq_to_pdu(q->flush_rq);
+
+ if (reg->ops->init_request(driver_data,
+ NULL, q->flush_rq, -1))
+ goto err_flush_rq;
+ }
+
if (blk_mq_init_hw_queues(q, reg, driver_data))
goto err_flush_rq;

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index b1cb3f4..a2e925b 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -474,11 +474,22 @@ static const struct device_attribute dev_attr_cache_type_rw =
__ATTR(cache_type, S_IRUGO|S_IWUSR,
virtblk_cache_type_show, virtblk_cache_type_store);

+static int virtblk_init_request(void *data, struct blk_mq_hw_ctx *hctx,
+ struct request *rq, unsigned int nr)
+{
+ struct virtio_blk *vblk = data;
+ struct virtblk_req *vbr = rq->special;
+
+ sg_init_table(vbr->sg, vblk->sg_elems);
+ return 0;
+}
+
static struct blk_mq_ops virtio_mq_ops = {
.queue_rq = virtio_queue_rq,
.map_queue = blk_mq_map_queue,
.alloc_hctx = blk_mq_alloc_single_hw_queue,
.free_hctx = blk_mq_free_single_hw_queue,
+ .init_request = virtblk_init_request,
.complete = virtblk_request_done,
};

@@ -490,15 +501,6 @@ static struct blk_mq_reg virtio_mq_reg = {
.flags = BLK_MQ_F_SHOULD_MERGE,
};

-static void virtblk_init_vbr(void *data, struct blk_mq_hw_ctx *hctx,
- struct request *rq, unsigned int nr)
-{
- struct virtio_blk *vblk = data;
- struct virtblk_req *vbr = rq->special;
-
- sg_init_table(vbr->sg, vblk->sg_elems);
-}
-
static int virtblk_probe(struct virtio_device *vdev)
{
struct virtio_blk *vblk;
@@ -562,8 +564,6 @@ static int virtblk_probe(struct virtio_device *vdev)
goto out_put_disk;
}

- blk_mq_init_commands(q, virtblk_init_vbr, vblk);
-
q->queuedata = vblk;

virtblk_name_format("vd", index, vblk->disk->disk_name, DISK_NAME_LEN);
diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h
index 2ff2e8d..cac10e1 100644
--- a/include/linux/blk-mq.h
+++ b/include/linux/blk-mq.h
@@ -66,6 +66,8 @@ typedef struct blk_mq_hw_ctx *(alloc_hctx_fn)(struct blk_mq_reg *,unsigned int);
typedef void (free_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
typedef int (init_hctx_fn)(struct blk_mq_hw_ctx *, void *, unsigned int);
typedef void (exit_hctx_fn)(struct blk_mq_hw_ctx *, unsigned int);
+typedef int (init_request_fn)(void *, struct blk_mq_hw_ctx *,
+ struct request *, unsigned int);

struct blk_mq_ops {
/*
@@ -98,6 +100,12 @@ struct blk_mq_ops {
*/
init_hctx_fn *init_hctx;
exit_hctx_fn *exit_hctx;
+
+ /*
+ * Called for every command allocated by the block layer to allow
+ * the driver to set up driver specific data.
+ */
+ init_request_fn *init_request;
};

enum {
@@ -117,7 +125,6 @@ enum {
struct request_queue *blk_mq_init_queue(struct blk_mq_reg *, void *);
int blk_mq_register_disk(struct gendisk *);
void blk_mq_unregister_disk(struct gendisk *);
-void blk_mq_init_commands(struct request_queue *, void (*init)(void *data, struct blk_mq_hw_ctx *, struct request *, unsigned int), void *data);

void blk_mq_flush_plug_list(struct blk_plug *plug, bool from_schedule);

--
1.7.10.4